jacques heilmann



I (No Model'.)

J. HEILMANN.

SYSTEM OF ELECTRICAL PROPULSION FOR VESSELS.

,325. Patented Apr. 12, 1898.

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UNITED STATES PATENT @rrrcn.

JEAN JACQUES IIEILMANN, OF PARIS, FRANCE.

SYSTEM OF ELECTRICAL PROPULSION FUR VESSELS.

SPECIFICATION forming part of Letters Patent No. 602,325, dated April12, 1898.

Application filed December 8, 1895. Serial No. 570,878. (No model.)Patented in Italy January 28, 1895, No. 38,132; in India April6,1895,N0, 111; in Russia April 29, 1895,110- 8,818; in Spain July1,1895,1 To.1'7,662; in Portugal July 19, 1895, No. 2,089, and inBelgium October 22,1895,N0.118,016.

T0 on whom it may concern:

Be it known that 1, JEAN J Aconns HEIL- MANN, engineer, residing at 19Rue Gambon, Paris, in the Republic of France, have in vented certain newand useful Improvements in a System of Electrical Propulsion forNavigable Vessels of all Kinds; and I do hereby declare the following tobe a full, clear, and exact description of the invention, such as willenable others skilled in the art to which it appertains to make and usethe same, reference being had to the accompanying drawings, and toletters of reference marked thereon, which form a part of thisspecification.

This invention has been patented in the following countries: Italy, No.38,182, dated January 28, 1895; India, N0. 111, dated April 6, 1895;Russia, No. 8,818, dated April 29, 1895; Spain, No. 17,662, dated July1, 1895; Portugal, No. 2,039, dated July 19, 1895, and Belgium, No.118,016, dated October 22, 1895.

This invention relates to a system of electrical propulsion fornavigable vessels of all kinds characterized by the use of one or morepropellers in each vessel rotated by means of electric motors suppliedwith current from an electrical generator, which is also carried uponthe same vessel. Either paddle-wheels or screws may be employed; but thelatter being more generally useful these improvements will be describedwith reference to them, and from this description the application topaddle-wheels will be obvious.

The accompanying drawings and diagrams illustrate my invention and willbe hereinafter referred to.

Figure 1 is a sectional plan of a vessel arranged to be propelledaccording to my system. Fig. 2 shows a modification. Fig. 3 is a diagramshowing the electric circuits of a single generator and motor. Fig. 1shows the circuits of two generators and motors.

Each screw-propeller A is driven by a series of electric motors B, whichare supplied with current from the main dynamos 0, cperated bysteam-engine D. The boilers are represented at D.

The engines are by this system not compelled to occupy a certainposition in the vessel nor to have their crank-shafts at a certainheight, and they maybe chosen of a perfectlybalanced type completelyexempt from vibrations. The propelling-screws A may be arranged in anysuitable and effective manner. Thus, as shown by Fig. 1, there may be asingle screw in line with the keel, or there may be twin screws arrangedwith the motors within the vessel, as in Fig. 2. In any case theordinary precautions are taken to secure the free action of the screwseffectively.

My improvements particularly relate to devices for permitting the vesselto be propelled at different speeds with a sensibly constant efficiency,the electrical apparatus being grouped in such a manner as to permit thesteamengine to rotate at a speed proportional to the work to be doneand, above all, with a constant steam admission. Fig. 3 represents,diagrammatically, a grouping of the electric devices which allows thisresultto be attained. For the sake of greater simplicity only one motor13 and one generating-dynamo G are shown, the armature of the dynamobeing in circuit with the motor without the intercalation of a rheostat.The field-coils I of the generator are in circuit with aseparatelydriven eXciter-dynamo E, which furnishes a current of constantpotential. The magnetism of the generator-field therefore depends uponthe current of the exciter. By means of a rheostat r, in series with thefield-coils I, the strength of the exciter-current can be varied, andhence the strength of the generator-field can be varied.

' The steam-engine which drives the generator has a constant steamadmissionthat is, at each stroke of the piston a predetermined quantityof steam at a constant pressure is admitted to the cylinder. Inasmuch asthe torque of the engine-shaft is directly proportional to thesteam-pressure it will remain constant. The speed of the engine willtherefore depend upon the torsional resistance which the constant torquemeet-s with. The work done by the engine is the product of the speed andthe steam-pressure. Hence if the constant-admission engine is calledupon to do more work it must increase in speed.

The work done by the generator is the product of the electromotive forceand its current. Now the electromotive force is proportional to thespeed of the engine. Hence the current is proportional to the torque ofthe engine. The engine having a constant torque, the generator willdeliver a constant current so long as the magnetism of its field remainsthe same. In a system of this kind the amperes of current supplied tothe motor will depend,therefore, upon the electromotive force of thecurrent. At low speeds the resistance of the motor-circuit is low, andhence the electromotive force of the constant-current generator can bereduced. Then the speed of the motor is to be increased, theelectromotive force of the generator must be increased in order toovercome the increased resistance of the motor due to its counterelectromotive force.

Now inasmuch as the electromotive force of the generator varies with thespeed of the engine and the speed of the engine depends upon thesteam-pressure and the torque of the generator, if the steam-pressure isconstant it is only necessary to vary the torque of the generator inorder to get either a greater or a less electromotive force. The torqueof the generator depending on the current and the magnetism of its fieldand the current being constant, it follows that by simply increasing ordiminishing the magnetism of the generator-field its torque willincrease or diminish. It is therefore possible to make the engine runslower or faster by increasing or diminishing the magnetism of thegeneratorfield. It follows that this simple manipulation of the rheostatr varies the electromotive force of the generator-current, andconsequently the speed of the motors. Hence when the vessel is to travelat a slow speed the strength of the generator-field is increased bymeans of the rheostat r. If, on the other hand,the speed of the vesselis to be increased, it is only necessary to diminish the strength of thegenerator-field and the motors will thus vary automatically with thework to be done. Fig. 4: shows, diagrammatically, in What way twogenerating-dynamos and two motors may be arranged.

F is a reversing-switch by means of which the direction of rotation ofthe motors may be changed by reversing the direction of the current inthe armatures of these motors.

\Vhen there are several propelling-screws, each of them may be rotatedseparately and there may be intercalated in each or any motor-currentvariable resistances. There may be employed all the ordinary rheostats,switches, resistances, and similar appliances commonly known and usedfor regulating the action of the electric motors, and moreparticularlyin the case of twin screws employed without a rudder, asindicated in Fig. 2, for the purpose of controlling the speeds and thestate of rest or motion of the respective motors. If the enginesemployed for driving the generating-dynamos have dead-centers, we mayutilize the eXciter for the purpose of starting the engines in thefollowing manner: The exciter being driven by a separate small engine iseasily moved, and the current from the eXciter is sent into thegenerating-dynamo, which is thereby momentarily converted into anelectric motor and by its rotation will start the generator-engine.

In Fig. 4, G is the double-pole switch, which can be employed for thispurpose.

The current from the generating-dynamo may be used for energizing motorsfor driving various machinery in different parts of the ship-such, forinstance, as the steeringgear.

Having now particularly described and ascertained the nature of my saidinvention and in what manner the same is performed, I declare that whatI claim is 1. In a system of electrical propulsion for navigablevessels, the combination with a pro peller-wheel, of a steam-enginehaving a constant steam admission, two or more generating-dynamos havingtheir armatures connected in multiple with the main conductors, anddriven by said steam-engine, a separatelydriven constantpotentialexciting-dynamo with which the field-coils of the main dynamos areconnected in multiple, a rheostat in series with the eXciter-armaturefor Varying the field strength of said dynamos, two or more electricmotors connected to the propeller-shaft, and having their field-coils inseries multiple with their armatures, and a reversing-switch between thefield-coils and the armatures of said motors, substantially as described.

2. In a system of electrical propulsion for navigable vessels, thecombination with a propeller-wheel, of a steam-engine having a constantsteam admission, a main generating-dynamo driven by said steam-engine, ascparately-driven constant-potential exciting-dynamo in circuit with thefield-coils of said main generator, a rheostat in series with theeXciter-armature for Varying the field-magnetism of the main generator,and an electric motor in series with the generator-armature and arrangedto drive the propeller-shaft,substantially as described.

111 testimony whereof I aflix my signature in presence of two witnesses.

JEAN JACQUES IIEILMANN.

W'itnesses:

CLYDE SHROPSHIRE, HENRY DANHERF.

IIO

